Pot burner



Feb. 26, 1946.

F. H. SCHNEIDER POT BURNER Filed April 5, 1944 5 'Sheets-Sheet l Feb. 26, 1946-.. F. H. SCHNEIDER POT BURNER Fild April 5, 1944` s sheets-sheet 2 Feb. 265, 1946. F. H. SCHNEIDER POT BURNER Filed April 5, 1944 5 sheets-sheet 3 0 Ae 8800 8 D m swmfm* l IH eo... o ,.M. a e No e o .0 o* o e e,- 0 0 .o Q M M M e 0 o Q O o .0 s e d 0 8 l 8 v 82 4 a.. 8800 e 8 9 9 a 4 S 90 O v5 /AQJM/a l I I I i I I'lhlll uw No //AW/ o a u. e Q M .MO e Q G w 0K se, e kann@ Patented Feb. 26, 1946 2.395.735 ro'r BURNER Frank H. Schneider, Gardner, Mass., assignor to Florence Stove Co., Gardner, Mass., a corporation of Massachusetts Application April 5, 19M, Serial No. 529,599

' (ci. 15s-91) 15 if This inventionrelates to an oil .burner and is known as a pot burner.

The pot burner usually consists of a circular pot-like structure having an imperforate bottom u into which the oil is fed and a perforated wall.

The oxygen necessary for combustion feeds inwardly through the perforations in the wall oi the burner to mingle with the volatile gases that are given oil by the fuel thereby forming a combustible mixture which burns progressively upward through the interior of the burner and to a greater or less degree above the top.

in the typical pot burner, one of the principal dilculties has been the inability of the ordinary design to produce complete combustion and, as a result, the heat output for the fuel consumed is not as great as it should be. 'I'his loss of eiliciency is also combined with relative inilexibility in the range through which the flame may be adjusted.

As a result, the typical pot burner has but limited usefulness.

It is with the view to overcoming the forego- Fig'. 2 shows a cross sectional view o1' the burnerin operation and the general nature of the llame produced thereby.

Fig. 3 is a side elevation of a modied form of down draft tube.

Fig. 4 is a side elevation of still another` form of down draft tube.

Referring now to the drawings, there is illustrated at 2 a stove casing which has a bottom 4 raised from the floor by supports, a door opening at 8 in which may be installed any suitable type of door, and a chimney opening at 8.

Maintained on the bottom 4 is a circular supporting housing I within which is suspended a pot burner made according to my invention and generally referred to as I2. The upper edge of supporting housing l0 is outwardly turned at I4 and on this supporting surface or flange rests an annular member I6 which, at its inner edge, bends downwardly in an inwardly slanting formation at I8. Extending through this circular tapered surfaee are a large number of air ports 2li, which will particularly concerned with that type of burner n a circular vertical flange to which is connected the circular shell 2i of the burner. This shell contains a series of circumferentially spaced primary air ports. The upper row of ports are designated 26, the next row of ports 28, the third row of ports 30 and the lowermost row of ports 32. It will be understood that the number of rows of ports may be varied and the number of holes around the cir.. cumference may likewise be changed as combustion requirements dider. It is intended, however, that the air ports that are provided will permit the admission of sumcient air to support combustion in the intended manner. y

The shell 2t has amxed thereto an imperforate bottom member 34 to which leads an oil supply line 38 connected to the bottom by any convenient means. A screw threaded connection is illustrated in the present case at 33. In the casing bottom 4 are air holes 4U and t2. 'I'hese holes'are large enough to permit the entrance to the interior of housing I0 of more than the amount of air necessary to maintain correct combustion.

'The air ports 32 do n'ot extend through the shell at right angles as is the case with ports 26, 28 and 30, but rather slope downwardly toward the interior along the angle indicated by the center line 33. The purpose of sloping theV holes inwardly in this manneris to cause the air entering the bottom of the burner when the iire is originally kindled to flow toward the bottom more readily thereby improving the combustion.

Extending inwardly from the inner side of shell 24 are a series of circumferentially spaced supports indicated at 44 at the lower level. and at 48 at the upper level. These supports carry pilot rings 48 and 50. Each pilot ring is in the form of a frustum of a cone with the base fitting closely within shell 24 and the top having a large central opening as at 52 in the lower ring and 54 in the upper ring. The pilot rings act as lbaiiles which assist in controlling the nature of the llames under different conditions oi combustion.

The description thus far has been that of a pot burner as is commonly known in the trade. Projecting downwardly into the center of the burner is what I term a down draft tube. This down draft tube may take the form of a. pipe such as 58 which leads from the atmosphere through the wall of the stove casing at 58, bending downwardly to be supported by a bracket 60. At a suitable distance above the top of the burner the pipe 56 is capped by a member S2 which has a substantial number of secondary air ports B4 extending about the circumference and directed substantially at secondary air ports 20. This arrangement with the air ports B4 aimed in the direction of the secondary air ports 20, may be termed an air spreader which causes the air issuing therefrom to impinge on the air coming from the ports 20. From the bottom central portion of cap 62, a smaller pipe B6, a continuation of pipe 56, extends downwardly into the center of the burner. The lower end of pipe 68 is preferably closed at 68, but there are a series of circumferentially extending perforations at 10, 12, and 14 through which air may pass laterally into the combustion chamber.

Pipe 66 may be removably connected with cap 62 by the threaded connection 16 and likewise the pipe 66 may be separable at 18 through the use of any convenient connecting means, one form of which is the bayonet `ioint illustrated at 80.

The operation of the construction described is as follows. Oil flows into the bottom 38 through oil supply pipe 36. The amount of oil that may enter the burner is controlled by automatic means which are well known in the art and which need not be described in this application. l

The oil in bottom 34 is ordinarily ignited by dropping a match therein but as the fuel is not particularly volatile except when heated, some little time will eiapse before the burner comes into full operation. At the outset, a sluggish flame is started which gradually strengthens. The oil vapors mix with air which flows to the combustion chamber through the openings 40 and 42 and the several rows of holes 2B, 28, 30 and 32. As combustion proceeds, the hot gases generated in the shell 24 rise. 'This causes a reduction in pressure which draws in additional air through the various air ports to provide the necessary mixture for continuous combustion.

As the flame gradually rises as the vaporization increases due to progressive heating of the bottom, it will be found that air will begin to enter the combustion chamber through the down draft tube 66. This tube, as previously stated. extends downwardly into the center of the pot. Since there is normally incomplete combustion in the center of a pot burner, the presence of tube 66, with its ports 10, 12, and 14, permits the entrance of additional air to the central area of the burner. The diameter of tube 66 is such that it does not impair combustion in any way. On the contrary, it aids the combustion because the incoming air is more evenly mixed with the vaporizing fuel.`

' 1f the centrally located tube 6B were not pres'- ent, it would be found that pulsations would occur. This is a condition in which, due to an uneven mixing of the fuel and air, the burning does not proceed constantly but rather in a pulsating manner. The presence of the center tube 66, however, provides suicient additional air through ports 1li, 12 and 14 so that a mixture which is continuously combustible is provided at all times.

Thus, the pulsations are completely eliminated.

At the outset of the operation, the initial flame produced in the space below the pilot ring may be in the nature of individual streams of fire as the air entering through ports 32 mingles at first with the oil vapors.

When, however, the flame has ascended to and within the upperportions of the burner, it will be found that the intermingling of the air entering through ports 28, 28 and 3U and ports 10. 12 and 1I produces such an evenly distributedv combustible mixture that the name appears as a solid sheet.

The pilotY rings IB and 50 direct the flames toward the-center and draft conditions are there by materially improved. However, the principal result of the invention is achieved by the inclusion and arrangement of the secondary air ports 20 and 64. The draft produced by the ascending heated and burned gases draws air in through ports 20 ina conical formation and likewise air is drawn downwardly in a corresponding conical formation through ports 6l.

These two sheets of air directed toward each other immediately mingle with unburned portions of the vaporized fuel and combustion immediately takes place. The circular flame burning lnwardly from the ports 20 impinges on the corresponding circular flame burning downwardly and outwardly from the ports 6d. At the circular ,line where the flames meet, they turn upwardly to form a solid tube of flame extending vertically from the cone of fire as illustrated in Fig. 2.

It has been found by test that the impingement of the flames from ports 20 and 5ft results in stabilizing both flames. That is to say they burn uniformly. Furthermore, thisimpingement results in a more active fire which improves combustion.

The angles at which the flames play against each other may be predetermined by the angle of ports 2u and 64. The size of the burner also may-be taken into account so that the angle of the ports will besuch that there will be proper engagement of the two cones of tire. l

However, regardless of the size of the pot the implngement ci the names one on the other as illustrated always improves combustion and provides an activeand stable fire because of the more complete mixture of the air and oil vapors.

The result of this novel pot burner construction which includes the down draft tube is that the Vaporized oil is substantially completely consumed giving a much higher degree of elciency than has heretofore been attained in a pot burner. Because of the complete combustion, the odor that is often associated with a. pot type burner is greatly minimized.

- Draft conditions are substantially improved by my construction which utilizes the center tube 66. It has been found by experiment that where two burners of the same size are used, one with a center tube and one without, there must be a considerably higher draft present in the second burner before it will give the same heat output as the first. This, of course, is due to the introduction of the additional air in the center part of the pot which improves the combustion as described.

When the oil is supplied at a maximum rate the cylindrical flame surrounding pipe 56 extends up above ports 84 a substantial distance and a clean white yellow flame is developed. As the oil supply is somewhat reduced the cylindrical.

keep bottom 34 suihciently hot to maintain proper vaporlzation and the burner is thus ready to be turned up to full heat when desired.

Insliigs. 3 and 4 are shown down draft tubes which may be used .when particular drafiwon- 'of the air along those surfaces which tend to carbonize will not only further improve combustion but will also eliminate carbon deposits.

In Fig. 3 the pipe 56 is shown, consisting of two halves which have been welded together along the ange t, the down draft tube tl is inserted within the lower end of pipe t and secured in place in any convenient manner. The

yassures :ria

air holes t2 correspond to the 4air holes 8d shown in Figs. 1 and 2, and are directed downwardly and outwardly toward the air holes 2t of the burner. Air holes 82 thus supply the downwardly extendins.r cone of air, which meets with the upwardly extending cone of air coming from air holes 2li to provide the improved combustion heretofore described. l

In order to eliminate `carbonizing above and below air holes 82, there is provided an upper set of holes lili extending circumferentially around the conically formed portion of tube Bil. These holes are drilled at an upward angle. so that air iiowing therethrough will pass upwardly upon lthe sides of pipe 5B. Similarly, holes tt are located circumferentially around the conical formation t8 to direct air upwardly along the portion of tube 8l lmmediatelythereabove. The portion of the down draft tube immediately below air holes t2 is made in a step-like formation and in the upwardly extending cone-like formations are additional air holes 90, 92, d@ and 9S. The air escaping from these holes streams upwardly along the walls at, itl), m2 and its, respectively, and facilitates combustion to an additional extent, so that carbon deposits along that portion of the tube below air holes t2 are held to a minimum.

The particular formation of the tube below air holes B2 may be varied, so long as extra air holes are provided below this level which are directed upwardly to drive air along the sides oi the tube; thus the conguration of Fig. 3 below holes d2 might be spiraled instead of the vstep formation disclosed.

In Fig. 4 is shown another modication, utilizing, however, the same principle., Here that portion of the tube below holes 92 is conical in form.

but the auxiliary holes i, itt. lili, il? and lili are all directed upwardly to cause air to act in a scavenging manner along the wall portions lit, H8, ld, 22 and il, respectively.

It has been found that the size of the principal air holes t2 that provide the maior name formation may be considerably larger than the auxiliary upwardly directed holes. However-,the exact size may be accurately determined when the particular draft conditions are known. Y

While particular forms of the invention have been shown and described, it is to be distinctly understood that the invention is not to be limited thereby, but only by the appended claims.

Iclaim: Y

1. An oil burner comprising a perforated shell closed at its bottom, means for supplying liquid fuel thereto, an axially located down draft tube extending downwardly into the center of said shell. the upper portion of said shell being perplaceasaid tube having a'. plurality of other periorations arranged circumferentially thereabout at a level above said shell and directed radially downwardly and outwardly-inv the general direction of the said perforations around the upper portion of said shell and additional perforations being provided in said shell and tube below said perforations in the upper portion of said shell.

2. A heating unit comprising a tubular supporting housing. a pot burner comprising a shell closed at the bottom and supported by and within said housing, means for permitting free flow of airl into the Space between said housing and burner, means for supplying said burner with liquid fuel, said shell having va plurality of apertures therethrough to permit the entrance of air to the interior of said burner, said apertures including a large number about fthe upper portion of said shell and directed radially inwardly, means for supplying air to the central area' of said burner comprising a down draft tube having a plurality of holes therethrough .and extending downwardly into the center of said burner with its remote end open to receive air, some of said holes being below the top of said burner and some of said holes being above the top of said iorated at a plurality of circumerentially located 75 at a level above said -draft tube having circumferentially burner, .said latter holes being directed radially outwardly and downwardly in the general dirgection of the holes at the upper portion of said urner.

3. An oil burner comprising a'perforated shell closed at the bottom, means for supplying liquid fuel to said shell, the perforations in the lower part of said shell constituting primary air ports and the air perforations in the upper periphery vof the shell directing the air supply inwardlyV and upwardly and constituting secondary airports, an additional source oi air comprising a tube located centrally with respect to said shell and extendingdownward into said shell to a point above the shell bottom, said tube having a plurality of perforations spaced circumferentially thereabout shell and directed outwardly and downwardly, and additional periorations in said tube located below the top of and within the connues of said shell.

4. An oil burner asset forth in claim 3, ln which said tube is connected directly to the atmosphere.

5. An oil burner comprising a perforated shell closed at the bottom, me for suppl liquid fuel thereto, said shell ha a finir? oi'l air ports extending about the upper mriphery of said shell, means for introducing an edtional amount of air within id shell and over Athe centrai area of said burner comp gs therethrough and extending downwardly into saidshell, some of said openings being the down draft tube that is of said shell and others oi ranged circumferentially about .e J. r do draft tube above the top of said shell, the longltual axes of the last mentioned opes exten generally in the direction of said air ports.

y 6. An oil burner compr a perforated shell closed at the bottom, means tor suppe liquid fuel tosaid shell, a down draft tube for providing additional air extending downwardly into and axlally of said shell. the upper portion of said shell having a plurality of holes arranged circumferentially and directed radially inwardly, said down arranged openings at a level above said shell directed radially outwardly in the'general 'direction o! the tures extending upwardly holes around the upper portion `of said shell, and additional holes in that part of the down draft tube that is within the connes of said shell.

7. An oil burner comprising a perforated shell closed at the bottom, means for supplying liquid fuel to said shell, the perforations about the lower part of said shell constituting primary air holes, the perforations about the upper periphery of said shell constituting secondary air holes, an

additional source of air comprising a down draft tube located centrally with respect to said shell and having a plurality oi' air ports located above said secondary air holes, the longitudinal axes of said air ports extending generally in the direction of said secondary air holes, said down draft tube having additional air ports both below and above said secondary air holes, the longitudinal axes of saidadditional air ports above said secondary air holes extending upwardly in coneshaped formation with respect to said down draft tube.

8. An oil burner comprising a perforated shell closed at the bottom, means fuel to said shell, those perforations through said shell below the top constituting primary air ports,

. axes of said airholes extending for supplying liquid y the other perforations about the top of said shell constituting secondary air ports, means for introducing an additional amount of air over the central area of said burner comprising a tube having a portion above said shell of generally downward ta ringv formation, a tubular extension from the bottom of said tapering formation extending downwardly within the confines of said shell, said tapering formation having a plurality of air ports located upper portion thereof, the axes of said air ports extending generally in the direction of said secondary air ports, said tapering formation having a substantial number of additional apertures lo lcated circumferentially thereabout below said plurality radiating outwardly and upwardly.

9. An oil burner comprising a perforated shell closed at the bottom, means for supplying liquid fuel to said shell, those perforations through the `nm'tion of the shell below the 'upper periphery constituting primary air ports, the perforations through the upper periphery of said shell constituting secondary air ports, means for introducing an additional amount of air over the centrai area of said burner comprising a tube axially located with respect to said shell and having a downwardly tapering step formation, said step formation having a plurality of air ports located circumferentially about the upper portion thereof, the axes of said ports extending downwardly and outwardly in the direction of said secondary i air ports, said tapered step formation having additional apertures through said steps both above and below said air porta'the axes ,of said aperin generally coneshaped formation.

l0. An oil burner comprising a perforated shell closed at the bottom, means for supplying liquid fuel to said shell, the perforations about the lower portion of said shell constituting primary air ports, the perforations'about the upper portion of said shell constituting secondary air ports, means for introducing an additional amount of air over the central area of said shell, said means comprising a tube having a portion above said shell which tapers downwardly, an extension from the lower end of said tapered formation located within and axially of said shell, said tapered portion having a plurality of air holes located circircumferentially about the of air ports, the axes of said apertures y assenso upper part thereof, the downwardly in the direction of said secondary air ports, said tapering portion having a substantial number oi apertures located circumferentially thereabout belew said air holes and distributed along said tapered formation, the axes of said apertures extending upwardly in conelike formation, said tube extension having additional apertures through that part that is within the confines of said shell and said tube at that part above the air holes of said tapered formation having additional apertures therethrough.

l1. An oil burner comprising a perforated shell closed at the bottom. means for supplying liquid fuel to said shell, said shell having a. line of upper perforations aboutv the upper periphery thereof, and lower perforations at levels therebelow, means between said upper and lower perforations providing a section of reduced area, a down draft tube located axially of said shell and extending down into said shell, said tube having a plurality of t holes therethrough and' extending radially thereabout in rows, the said holes of atleast one row located above said upper perforations having their axes directed downwardly and outwardly in the direction of said upper perforations, and other rows 'of holes below said one row having their axes directed upwardly and outwardly in coneshaped formation.

12. An cil burner comprising a perforated shell closed at the bottom, means for supplying liquid fuel to said shell, said shell having a line of upper perforations about the upper periphery thereof, and lower perforations at levels therebelow, means between said upper and lower perforations pro viding a section of reduced area, a down draft cumferentlally about the tube located axially of said shell and extending ing their axes directed upwardly and outwardly l in cone-shaped formation.

i3. An oil burner comprising a perforated shell closed at the bottom, means for supplying liquid fuel to said shell, said shell havingcJ line of upper perforations about the upper periphery thereof.

and lower perforations at levels therebelow, means y' between said upper and lower perforations pro- 'vlding a section of reduced area, a down draft tube located axially of said shell and extending down into said shell. said tube having at least one outwardly extending shoulder with holes therethrough with their axes directed upwardly, a`

downwardly tapering portion below said shoulder with ports therethrough with their axes directed downwardly and outwardly toward said upper perforations, said tube having portions of reduced diameter below said ports with apertures therethrough, the axes of which are directed upwardly.

le. An oil burner comprising a perforated shell closed at the bottom, means for supplying liquid -fuel to said shell, said shell having a line of upper perforations about the upper periphery thereof. and lower perforations at levels therebelow, means betweensaid upper and lower perforations providing a section of reduced area, a down draft tube located axially of said shell and extending down into said shell, said tube having an outwardly extending shoulder with perforations 2,895,795 v 5ft and lower perforations at levels therebelow, a 1

down draft tube located axially of said shell and extending down into said shell, said tube having a plurality of holes therethrough and extending radially thereabout in rows, said holes spaced with one row located above said upper perforations and 5 having their axes directed downwardly and outwardly in the direction of said upper perforations and other rows of holes below said one row 'having their axes directed upwardly and outwardly in cone-shaped formation.

FRANK H. SCHNEIDER. 

